diff --git a/static/app/components/feedback/useMutateFeedback.tsx b/static/app/components/feedback/useMutateFeedback.tsx
index 16c72547ad3a..5ffc925eccf6 100644
--- a/static/app/components/feedback/useMutateFeedback.tsx
+++ b/static/app/components/feedback/useMutateFeedback.tsx
@@ -7,6 +7,7 @@ import type {Actor} from 'sentry/types/core';
 import type {GroupStatus} from 'sentry/types/group';
 import type {Organization} from 'sentry/types/organization';
 import {parseQueryKey} from 'sentry/utils/api/apiQueryKey';
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {fetchMutation} from 'sentry/utils/queryClient';
 
 type TFeedbackIds = 'all' | string[];
@@ -35,8 +36,12 @@ export function useMutateFeedback({feedbackIds, organization, projectIds}: Props
     mutationFn: ([ids, payload]) => {
       const isSingleId = ids !== 'all' && ids.length === 1;
       const url = isSingleId
-        ? `/organizations/${organization.slug}/issues/${ids[0]}/`
-        : `/organizations/${organization.slug}/issues/`;
+        ? getApiUrl('/organizations/$organizationIdOrSlug/issues/$issueId/', {
+            path: {organizationIdOrSlug: organization.slug, issueId: String(ids[0])},
+          })
+        : getApiUrl('/organizations/$organizationIdOrSlug/issues/', {
+            path: {organizationIdOrSlug: organization.slug},
+          });
 
       // TODO: it would be excellent if `PUT /issues/` could return the same data
       // as `GET /issues/` when query params are set. IE: it should expand inbox & owners
diff --git a/static/app/components/onboarding/createSampleEventButton.tsx b/static/app/components/onboarding/createSampleEventButton.tsx
index a16e7c72a373..37bdf48d665e 100644
--- a/static/app/components/onboarding/createSampleEventButton.tsx
+++ b/static/app/components/onboarding/createSampleEventButton.tsx
@@ -14,6 +14,7 @@ import {t} from 'sentry/locale';
 import type {Project} from 'sentry/types/project';
 import {trackAnalytics} from 'sentry/utils/analytics';
 import {apiOptions} from 'sentry/utils/api/apiOptions';
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {fetchMutation} from 'sentry/utils/queryClient';
 import {normalizeUrl} from 'sentry/utils/url/normalizeUrl';
 import {useNavigate} from 'sentry/utils/useNavigate';
@@ -57,7 +58,12 @@ export function CreateSampleEventButton({
 
   const {mutate: createSampleGroup, isPending} = useMutation({
     mutationFn: () => {
-      const url = `/projects/${organization.slug}/${project!.slug}/create-sample/`;
+      const url = getApiUrl(
+        '/projects/$organizationIdOrSlug/$projectIdOrSlug/create-sample/',
+        {
+          path: {organizationIdOrSlug: organization.slug, projectIdOrSlug: project!.slug},
+        }
+      );
       return fetchMutation<{groupID: string}>({method: 'POST', url});
     },
     onMutate() {
diff --git a/static/app/components/replays/table/replayBulkViewedActions.tsx b/static/app/components/replays/table/replayBulkViewedActions.tsx
index e4b1be7c387a..f26bd4ab55b1 100644
--- a/static/app/components/replays/table/replayBulkViewedActions.tsx
+++ b/static/app/components/replays/table/replayBulkViewedActions.tsx
@@ -8,6 +8,7 @@ import {LoadingIndicator} from 'sentry/components/loadingIndicator';
 import {IconCheckmark} from 'sentry/icons';
 import {t, tn} from 'sentry/locale';
 import {trackAnalytics} from 'sentry/utils/analytics';
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import type {ListCheckboxQueryKeyRef} from 'sentry/utils/list/useListItemCheckboxState';
 import {fetchMutation} from 'sentry/utils/queryClient';
 import {replayListApiOptions} from 'sentry/utils/replays/replayListApiOptions';
@@ -40,7 +41,16 @@ export function ReplayBulkViewedActions({
 
     const results = await Promise.allSettled(
       selectedRows.map(replay => {
-        const url = `/projects/${organization.slug}/${replay.project_id}/replays/${replay.id}/viewed-by/`;
+        const url = getApiUrl(
+          '/projects/$organizationIdOrSlug/$projectIdOrSlug/replays/$replayId/viewed-by/',
+          {
+            path: {
+              organizationIdOrSlug: organization.slug,
+              projectIdOrSlug: String(replay.project_id),
+              replayId: replay.id,
+            },
+          }
+        );
 
         return fetchMutation({method: 'POST', url}).then(() => replay.id);
       })
diff --git a/static/app/components/searchQueryBuilder/askSeerCombobox/askSeerComboBox.spec.tsx b/static/app/components/searchQueryBuilder/askSeerCombobox/askSeerComboBox.spec.tsx
index f15584474edc..c5892126fa39 100644
--- a/static/app/components/searchQueryBuilder/askSeerCombobox/askSeerComboBox.spec.tsx
+++ b/static/app/components/searchQueryBuilder/askSeerCombobox/askSeerComboBox.spec.tsx
@@ -14,6 +14,7 @@ import {
   useSearchQueryBuilderAI,
 } from 'sentry/components/searchQueryBuilder/context';
 import * as analytics from 'sentry/utils/analytics';
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {fetchMutation} from 'sentry/utils/queryClient';
 import {GlobalFeedbackForm} from 'sentry/utils/useFeedbackForm';
 import {
@@ -36,7 +37,9 @@ const askSeerMutationOptions = mutationOptions({
       status: string;
       unsupported_reason: string | null;
     }>({
-      url: '/organizations/org-slug/trace-explorer-ai/query/',
+      url: getApiUrl('/organizations/$organizationIdOrSlug/trace-explorer-ai/query/', {
+        path: {organizationIdOrSlug: 'org-slug'},
+      }),
       method: 'POST',
       data: {},
     });
diff --git a/static/app/components/searchQueryBuilder/index.spec.tsx b/static/app/components/searchQueryBuilder/index.spec.tsx
index f6771c6393f8..8953517fe9f5 100644
--- a/static/app/components/searchQueryBuilder/index.spec.tsx
+++ b/static/app/components/searchQueryBuilder/index.spec.tsx
@@ -36,6 +36,7 @@ import {
 import {InvalidReason, WildcardOperators} from 'sentry/components/searchSyntax/parser';
 import {SavedSearchType, type TagCollection} from 'sentry/types/group';
 import * as analytics from 'sentry/utils/analytics';
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {
   FieldKey,
   FieldKind,
@@ -7409,7 +7410,12 @@ describe('SearchQueryBuilder', () => {
                     status: string;
                     unsupported_reason: string | null;
                   }>({
-                    url: '/organizations/org-slug/trace-explorer-ai/query/',
+                    url: getApiUrl(
+                      '/organizations/$organizationIdOrSlug/trace-explorer-ai/query/',
+                      {
+                        path: {organizationIdOrSlug: 'org-slug'},
+                      }
+                    ),
                     method: 'POST',
                     data: {},
                   });
diff --git a/static/app/utils/api/knownGetsentryApiUrls.ts b/static/app/utils/api/knownGetsentryApiUrls.ts
index eb2b6008af5d..802631be31ef 100644
--- a/static/app/utils/api/knownGetsentryApiUrls.ts
+++ b/static/app/utils/api/knownGetsentryApiUrls.ts
@@ -11,6 +11,7 @@ export type KnownGetsentryApiUrls =
   | '/_admin/cells/$region/invoice-comparison/'
   | '/_admin/cells/$region/queue-spike-projection-batch/'
   | '/_admin/customers/$organizationIdOrSlug/balance-changes/'
+  | '/_admin/customers/$organizationIdOrSlug/billing-platform-migration/'
   | '/_admin/customers/$organizationIdOrSlug/queue-spike-projection/'
   | '/_admin/instance-level-oauth/'
   | '/_admin/users/$userId/suspend/'
@@ -33,6 +34,7 @@ export type KnownGetsentryApiUrls =
   | '/customers/$organizationIdOrSlug/billing-details/'
   | '/customers/$organizationIdOrSlug/billing-seats/current/'
   | '/customers/$organizationIdOrSlug/charges/'
+  | '/customers/$organizationIdOrSlug/delete-billing-metric-history/'
   | '/customers/$organizationIdOrSlug/history/'
   | '/customers/$organizationIdOrSlug/history/current/'
   | '/customers/$organizationIdOrSlug/invoices/'
diff --git a/static/app/utils/integrationUtil.tsx b/static/app/utils/integrationUtil.tsx
index 88c7b64a417a..7ee20bb0479d 100644
--- a/static/app/utils/integrationUtil.tsx
+++ b/static/app/utils/integrationUtil.tsx
@@ -325,23 +325,6 @@ export const getAlertText = (integrations?: Integration[]): string | undefined =
   }
 };
 
-/**
- * Uses the mapping and baseEndpoint to derive the details for the mappings request.
- * @param baseEndpoint Must have a trailing slash, since the id is appended for PUT requests!
- * @param mapping The mapping or suggestion being sent to the endpoint
- * @returns An object containing the request method (apiMethod), and final endpoint (apiEndpoint)
- */
-export const getExternalActorEndpointDetails = (
-  baseEndpoint: string,
-  mapping?: ExternalActorMappingOrSuggestion
-): {apiEndpoint: string; apiMethod: 'POST' | 'PUT'} => {
-  const isValidMapping = mapping && isExternalActorMapping(mapping);
-  return {
-    apiMethod: isValidMapping ? 'PUT' : 'POST',
-    apiEndpoint: isValidMapping ? `${baseEndpoint}${mapping.id}/` : baseEndpoint,
-  };
-};
-
 export function getIntegrationStatus(integration: Integration) {
   // there are multiple status fields for an integration we consider
   const statusList = [integration.organizationIntegrationStatus, integration.status];
diff --git a/static/app/utils/queryClient.tsx b/static/app/utils/queryClient.tsx
index 1b366a9bd88f..ed66279561ff 100644
--- a/static/app/utils/queryClient.tsx
+++ b/static/app/utils/queryClient.tsx
@@ -13,6 +13,7 @@ import {apiFetch} from 'sentry/utils/api/apiFetch';
 import {selectJson} from 'sentry/utils/api/apiOptions';
 import {normalizeQueryKey} from 'sentry/utils/api/apiQueryKey';
 import type {ApiQueryKey, QueryKeyEndpointOptions} from 'sentry/utils/api/apiQueryKey';
+import type {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {RequestError} from 'sentry/utils/requestError/requestError';
 
 const nonRetryCodes = new Set<number | undefined>([400, 401, 402, 403, 404]);
@@ -155,7 +156,7 @@ export function setApiQueryData<TResponseData>(
 
 type ApiMutationVariables = {
   method: 'PUT' | 'POST' | 'PATCH' | 'DELETE';
-  url: string;
+  url: ReturnType<typeof getApiUrl>;
   data?: Record<string, unknown>;
   options?: Pick<
     QueryKeyEndpointOptions,
diff --git a/static/app/utils/replays/hooks/useMarkReplayViewed.tsx b/static/app/utils/replays/hooks/useMarkReplayViewed.tsx
index 3781fa2fc427..e1be174c4d62 100644
--- a/static/app/utils/replays/hooks/useMarkReplayViewed.tsx
+++ b/static/app/utils/replays/hooks/useMarkReplayViewed.tsx
@@ -1,5 +1,6 @@
 import {useMutation, useQueryClient} from '@tanstack/react-query';
 
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {fetchMutation} from 'sentry/utils/queryClient';
 import {useOrganization} from 'sentry/utils/useOrganization';
 
@@ -13,11 +14,29 @@ export function useMarkReplayViewed() {
 
   return useMutation<TData, TError, TVariables>({
     mutationFn: ({projectSlug, replayId}) => {
-      const url = `/projects/${organization.slug}/${projectSlug}/replays/${replayId}/viewed-by/`;
+      const url = getApiUrl(
+        '/projects/$organizationIdOrSlug/$projectIdOrSlug/replays/$replayId/viewed-by/',
+        {
+          path: {
+            organizationIdOrSlug: organization.slug,
+            projectIdOrSlug: projectSlug,
+            replayId,
+          },
+        }
+      );
       return fetchMutation({method: 'POST', url});
     },
     onSuccess(_data, {projectSlug, replayId}) {
-      const url = `/projects/${organization.slug}/${projectSlug}/replays/${replayId}/viewed-by/`;
+      const url = getApiUrl(
+        '/projects/$organizationIdOrSlug/$projectIdOrSlug/replays/$replayId/viewed-by/',
+        {
+          path: {
+            organizationIdOrSlug: organization.slug,
+            projectIdOrSlug: projectSlug,
+            replayId,
+          },
+        }
+      );
       queryClient.refetchQueries({queryKey: [url]});
     },
     retry: false,
diff --git a/static/app/views/issueDetails/discardIssueMutationOptions.ts b/static/app/views/issueDetails/discardIssueMutationOptions.ts
index c3a8995ff4f7..776d1981ceea 100644
--- a/static/app/views/issueDetails/discardIssueMutationOptions.ts
+++ b/static/app/views/issueDetails/discardIssueMutationOptions.ts
@@ -4,6 +4,7 @@ import {addLoadingMessage, clearIndicators} from 'sentry/actionCreators/indicato
 import {t} from 'sentry/locale';
 import {GroupStore} from 'sentry/stores/groupStore';
 import {IssueListCacheStore} from 'sentry/stores/IssueListCacheStore';
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {uniqueId} from 'sentry/utils/guid';
 import {fetchMutation} from 'sentry/utils/queryClient';
 import type {useNavigate} from 'sentry/utils/useNavigate';
@@ -23,7 +24,12 @@ export function discardIssueMutationOptions({
     mutationFn: (variables: DiscardIssueVariables) =>
       fetchMutation({
         method: 'PUT',
-        url: `/issues/${variables.groupId}/`,
+        url: getApiUrl('/organizations/$organizationIdOrSlug/issues/$issueId/', {
+          path: {
+            organizationIdOrSlug: variables.orgSlug,
+            issueId: String(variables.groupId),
+          },
+        }),
         data: {discard: true},
       }),
     onMutate: variables => {
diff --git a/static/app/views/preprod/buildComparison/buildComparison.tsx b/static/app/views/preprod/buildComparison/buildComparison.tsx
index 75c9333803c1..059149913d76 100644
--- a/static/app/views/preprod/buildComparison/buildComparison.tsx
+++ b/static/app/views/preprod/buildComparison/buildComparison.tsx
@@ -60,7 +60,11 @@ export default function BuildComparison() {
     RequestError
   >({
     mutationFn: () => {
-      return fetchMutation({url: `${compareUrl}?rerun=true`, method: 'POST'});
+      return fetchMutation({
+        url: compareUrl,
+        method: 'POST',
+        options: {query: {rerun: 'true'}},
+      });
     },
     onSuccess: response => {
       if (response?.status === 'exists') {
diff --git a/static/app/views/settings/organizationApiKeys/organizationApiKeyDetails.tsx b/static/app/views/settings/organizationApiKeys/organizationApiKeyDetails.tsx
index 6661d0d40ec6..55102a74f2ff 100644
--- a/static/app/views/settings/organizationApiKeys/organizationApiKeyDetails.tsx
+++ b/static/app/views/settings/organizationApiKeys/organizationApiKeyDetails.tsx
@@ -13,6 +13,7 @@ import {SentryDocumentTitle} from 'sentry/components/sentryDocumentTitle';
 import {API_ACCESS_SCOPES} from 'sentry/constants';
 import {t} from 'sentry/locale';
 import {apiOptions} from 'sentry/utils/api/apiOptions';
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {fetchMutation} from 'sentry/utils/queryClient';
 import {useNavigate} from 'sentry/utils/useNavigate';
 import {useOrganization} from 'sentry/utils/useOrganization';
@@ -82,7 +83,9 @@ function OrganizationApiKeyForm({
   const mutation = useMutation({
     mutationFn: (data: ApiKeyFormValues) =>
       fetchMutation<DeprecatedApiKey>({
-        url: `/organizations/${organizationSlug}/api-keys/${apiKey.id}/`,
+        url: getApiUrl('/organizations/$organizationIdOrSlug/api-keys/$apiKeyId/', {
+          path: {organizationIdOrSlug: organizationSlug, apiKeyId: apiKey.id},
+        }),
         method: 'PUT',
         data,
       }),
diff --git a/static/app/views/settings/organizationIntegrations/integrationExternalMappingForm.spec.tsx b/static/app/views/settings/organizationIntegrations/integrationExternalMappingForm.spec.tsx
index b2aac3f6832c..2f69011fe4f6 100644
--- a/static/app/views/settings/organizationIntegrations/integrationExternalMappingForm.spec.tsx
+++ b/static/app/views/settings/organizationIntegrations/integrationExternalMappingForm.spec.tsx
@@ -10,14 +10,25 @@ import {
   ModalFooter,
 } from '@sentry/scraps/modal';
 
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
+
 import {IntegrationExternalMappingForm} from './integrationExternalMappingForm';
 
 describe('IntegrationExternalMappingForm', () => {
-  const membersEndpoint = '/organizations/org-slug/members/';
+  const membersEndpoint = getApiUrl('/organizations/$organizationIdOrSlug/members/', {
+    path: {organizationIdOrSlug: 'org-slug'},
+  });
   const teamsEndpoint = '/organizations/org-slug/teams/';
+  const memberEndpoint = (memberId: string) =>
+    getApiUrl('/organizations/$organizationIdOrSlug/members/$memberId/', {
+      path: {organizationIdOrSlug: 'org-slug', memberId},
+    });
   const baseProps = {
     integration: GitHubIntegrationFixture(),
-    getBaseFormEndpoint: jest.fn(_mapping => membersEndpoint),
+    // Callers own the whole url, so an existing mapping resolves to its own resource.
+    getBaseFormEndpoint: jest.fn(mapping =>
+      mapping && 'id' in mapping ? memberEndpoint(mapping.id) : membersEndpoint
+    ),
   } satisfies Partial<React.ComponentProps<typeof IntegrationExternalMappingForm>>;
 
   const closeModal = jest.fn();
@@ -74,7 +85,7 @@ describe('IntegrationExternalMappingForm', () => {
       body: {},
     });
     putResponse = MockApiClient.addMockResponse({
-      url: `${membersEndpoint}1/`,
+      url: memberEndpoint('1'),
       method: 'PUT',
       body: {},
     });
diff --git a/static/app/views/settings/organizationIntegrations/integrationExternalMappingForm.tsx b/static/app/views/settings/organizationIntegrations/integrationExternalMappingForm.tsx
index dab539e22ce6..1a09f3b611cb 100644
--- a/static/app/views/settings/organizationIntegrations/integrationExternalMappingForm.tsx
+++ b/static/app/views/settings/organizationIntegrations/integrationExternalMappingForm.tsx
@@ -21,10 +21,8 @@ import type {
 } from 'sentry/types/integrations';
 import type {Member, Team} from 'sentry/types/organization';
 import {apiOptions} from 'sentry/utils/api/apiOptions';
-import {
-  getExternalActorEndpointDetails,
-  isExternalActorMapping,
-} from 'sentry/utils/integrationUtil';
+import type {getApiUrl} from 'sentry/utils/api/getApiUrl';
+import {isExternalActorMapping} from 'sentry/utils/integrationUtil';
 import {fetchMutation} from 'sentry/utils/queryClient';
 import {RequestError} from 'sentry/utils/requestError/requestError';
 import {requestErrorToFieldErrors} from 'sentry/utils/requestError/requestErrorToFieldErrors';
@@ -34,7 +32,9 @@ import {useOrganization} from 'sentry/utils/useOrganization';
 type SentrySelection = {id: string; name: string};
 
 type BaseProps = {
-  getBaseFormEndpoint: (mapping?: ExternalActorMappingOrSuggestion) => string;
+  getBaseFormEndpoint: (
+    mapping?: ExternalActorMappingOrSuggestion
+  ) => ReturnType<typeof getApiUrl>;
   integration: Integration;
   type: 'user' | 'team';
   defaultOptions?: Array<{label: React.ReactNode; value: SentrySelection}>;
@@ -182,14 +182,11 @@ function InlineMappingForm({
         initialValue={initialValue}
         mutationOptions={{
           mutationFn: ({sentryId}: {sentryId: SentrySelection}) => {
+            const isValidMapping = Object.hasOwn(mapping || {}, 'id');
             const fullData = buildMutationData(mapping, integration, type, sentryId);
-            const {apiEndpoint, apiMethod} = getExternalActorEndpointDetails(
-              getBaseFormEndpoint(fullData as ExternalActorMappingOrSuggestion),
-              fullData as ExternalActorMappingOrSuggestion
-            );
             return fetchMutation<ExternalActorMapping>({
-              url: apiEndpoint,
-              method: apiMethod,
+              url: getBaseFormEndpoint(fullData as ExternalActorMappingOrSuggestion),
+              method: isValidMapping ? 'PUT' : 'POST',
               data: fullData,
             });
           },
@@ -264,6 +261,7 @@ function ModalMappingForm({
       externalName: string;
       sentryId: SentrySelection;
     }) => {
+      const isValidMapping = mapping && Object.hasOwn(mapping || {}, 'id');
       const fullData = buildMutationData(
         mapping,
         integration,
@@ -271,13 +269,9 @@ function ModalMappingForm({
         sentryId,
         externalName
       );
-      const {apiEndpoint, apiMethod} = getExternalActorEndpointDetails(
-        getBaseFormEndpoint(fullData as ExternalActorMappingOrSuggestion),
-        fullData as ExternalActorMappingOrSuggestion
-      );
       return fetchMutation<ExternalActorMapping>({
-        url: apiEndpoint,
-        method: apiMethod,
+        url: getBaseFormEndpoint(fullData as ExternalActorMappingOrSuggestion),
+        method: isValidMapping ? 'PUT' : 'POST',
         data: fullData,
       });
     },
diff --git a/static/app/views/settings/organizationIntegrations/integrationExternalMappings.spec.tsx b/static/app/views/settings/organizationIntegrations/integrationExternalMappings.spec.tsx
index 2c6ab5380401..aebbec91b584 100644
--- a/static/app/views/settings/organizationIntegrations/integrationExternalMappings.spec.tsx
+++ b/static/app/views/settings/organizationIntegrations/integrationExternalMappings.spec.tsx
@@ -9,6 +9,8 @@ import {
   waitForElementToBeRemoved,
 } from 'sentry-test/reactTestingLibrary';
 
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
+
 import {IntegrationExternalMappings} from './integrationExternalMappings';
 
 describe('IntegrationExternalMappings', () => {
@@ -105,7 +107,11 @@ describe('IntegrationExternalMappings', () => {
         onCreate={onCreateMock}
         onDelete={onDeleteMock}
         defaultOptions={[]}
-        getBaseFormEndpoint={() => '/organizations/org-slug/codeowners-associations/'}
+        getBaseFormEndpoint={() =>
+          getApiUrl('/organizations/$organizationIdOrSlug/codeowners-associations/', {
+            path: {organizationIdOrSlug: organization.slug},
+          })
+        }
       />
     );
 
@@ -123,7 +129,11 @@ describe('IntegrationExternalMappings', () => {
         onCreate={onCreateMock}
         onDelete={onDeleteMock}
         defaultOptions={[]}
-        getBaseFormEndpoint={() => '/organizations/org-slug/codeowners-associations/'}
+        getBaseFormEndpoint={() =>
+          getApiUrl('/organizations/$organizationIdOrSlug/codeowners-associations/', {
+            path: {organizationIdOrSlug: organization.slug},
+          })
+        }
       />
     );
 
@@ -144,7 +154,11 @@ describe('IntegrationExternalMappings', () => {
         onCreate={onCreateMock}
         onDelete={onDeleteMock}
         defaultOptions={[]}
-        getBaseFormEndpoint={() => '/organizations/org-slug/codeowners-associations/'}
+        getBaseFormEndpoint={() =>
+          getApiUrl('/organizations/$organizationIdOrSlug/codeowners-associations/', {
+            path: {organizationIdOrSlug: organization.slug},
+          })
+        }
       />
     );
 
@@ -174,7 +188,11 @@ describe('IntegrationExternalMappings', () => {
         onCreate={onCreateMock}
         onDelete={onDeleteMock}
         defaultOptions={[]}
-        getBaseFormEndpoint={() => '/organizations/org-slug/codeowners-associations/'}
+        getBaseFormEndpoint={() =>
+          getApiUrl('/organizations/$organizationIdOrSlug/codeowners-associations/', {
+            path: {organizationIdOrSlug: organization.slug},
+          })
+        }
       />
     );
     renderGlobalModal();
diff --git a/static/app/views/settings/organizationIntegrations/integrationExternalTeamMappings.tsx b/static/app/views/settings/organizationIntegrations/integrationExternalTeamMappings.tsx
index c680a2be57e9..97eee1cfa0fc 100644
--- a/static/app/views/settings/organizationIntegrations/integrationExternalTeamMappings.tsx
+++ b/static/app/views/settings/organizationIntegrations/integrationExternalTeamMappings.tsx
@@ -1,4 +1,4 @@
-import {useQuery, useMutation} from '@tanstack/react-query';
+import {skipToken, useQuery, useMutation} from '@tanstack/react-query';
 
 import {useModal} from '@sentry/scraps/modal';
 
@@ -126,7 +126,9 @@ export function IntegrationExternalTeamMappings(props: Props) {
 
   const getBaseFormEndpoint = (mapping?: ExternalActorMappingOrSuggestion) => {
     if (!mapping) {
-      return '';
+      return getApiUrl('/teams/$organizationIdOrSlug/$teamIdOrSlug/external-teams/', {
+        path: skipToken,
+      });
     }
     // Search both initialResults and teams (filtered by hasExternalTeams).
     // Fall back to sentryName from the mutation data for teams found via search
@@ -135,12 +137,24 @@ export function IntegrationExternalTeamMappings(props: Props) {
       initialResults?.find(item => item.id === mapping.teamId) ??
       teams.find(item => item.id === mapping.teamId);
     const teamSlug = team?.slug ?? ('sentryName' in mapping ? mapping.sentryName : '');
-    return getApiUrl('/teams/$organizationIdOrSlug/$teamIdOrSlug/external-teams/', {
-      path: {
-        organizationIdOrSlug: organization.slug,
-        teamIdOrSlug: teamSlug,
-      },
-    });
+    const externalTeamId = 'id' in mapping ? mapping.id : null;
+    return externalTeamId
+      ? getApiUrl(
+          '/teams/$organizationIdOrSlug/$teamIdOrSlug/external-teams/$externalTeamId/',
+          {
+            path: {
+              organizationIdOrSlug: organization.slug,
+              teamIdOrSlug: teamSlug,
+              externalTeamId,
+            },
+          }
+        )
+      : getApiUrl('/teams/$organizationIdOrSlug/$teamIdOrSlug/external-teams/', {
+          path: {
+            organizationIdOrSlug: organization.slug,
+            teamIdOrSlug: teamSlug,
+          },
+        });
   };
 
   const onCreate = () => {
diff --git a/static/app/views/settings/organizationIntegrations/integrationExternalUserMappings.tsx b/static/app/views/settings/organizationIntegrations/integrationExternalUserMappings.tsx
index e119cf48b653..c77dc0758e6d 100644
--- a/static/app/views/settings/organizationIntegrations/integrationExternalUserMappings.tsx
+++ b/static/app/views/settings/organizationIntegrations/integrationExternalUserMappings.tsx
@@ -9,6 +9,7 @@ import {LoadingIndicator} from 'sentry/components/loadingIndicator';
 import {t} from 'sentry/locale';
 import type {
   ExternalActorMapping,
+  ExternalActorMappingOrSuggestion,
   ExternalUser,
   Integration,
 } from 'sentry/types/integrations';
@@ -34,12 +35,20 @@ export function IntegrationExternalUserMappings(props: Props) {
   const organization = useOrganization();
   const location = useLocation();
 
-  const BASE_FORM_ENDPOINT = getApiUrl(
-    '/organizations/$organizationIdOrSlug/external-users/',
-    {
-      path: {organizationIdOrSlug: organization.slug},
-    }
-  );
+  // An existing mapping is updated in place, so the id belongs in the path.
+  const getBaseFormEndpoint = (mapping?: ExternalActorMappingOrSuggestion) => {
+    const externalUserId = mapping && 'id' in mapping ? mapping.id : null;
+    return externalUserId
+      ? getApiUrl(
+          '/organizations/$organizationIdOrSlug/external-users/$externalUserId/',
+          {
+            path: {organizationIdOrSlug: organization.slug, externalUserId},
+          }
+        )
+      : getApiUrl('/organizations/$organizationIdOrSlug/external-users/', {
+          path: {organizationIdOrSlug: organization.slug},
+        });
+  };
   // We paginate on this query, since we're filtering by hasExternalTeams:true
   const {
     data,
@@ -141,7 +150,7 @@ export function IntegrationExternalUserMappings(props: Props) {
         {...modalProps}
         type="user"
         integration={integration}
-        getBaseFormEndpoint={() => BASE_FORM_ENDPOINT}
+        getBaseFormEndpoint={getBaseFormEndpoint}
         defaultOptions={defaultUserOptions}
         onSubmitSuccess={handleSubmitSuccess}
       />
@@ -154,7 +163,7 @@ export function IntegrationExternalUserMappings(props: Props) {
         type="user"
         integration={integration}
         mappings={mappings()}
-        getBaseFormEndpoint={() => BASE_FORM_ENDPOINT}
+        getBaseFormEndpoint={getBaseFormEndpoint}
         defaultOptions={defaultUserOptions}
         onCreate={openMembersModal}
         onDelete={deleteMutation.mutate}
diff --git a/static/app/views/unsubscribe/issue.spec.tsx b/static/app/views/unsubscribe/issue.spec.tsx
index 511ea8c85417..f0197c8f3f67 100644
--- a/static/app/views/unsubscribe/issue.spec.tsx
+++ b/static/app/views/unsubscribe/issue.spec.tsx
@@ -8,7 +8,7 @@ describe('UnsubscribeIssue', () => {
 
   beforeEach(() => {
     mockUpdate = MockApiClient.addMockResponse({
-      url: '/organizations/acme/unsubscribe/issue/9876/?_=signature-value',
+      url: '/organizations/acme/unsubscribe/issue/9876/',
       method: 'POST',
       status: 201,
     });
@@ -57,8 +57,11 @@ describe('UnsubscribeIssue', () => {
     await userEvent.click(button);
 
     expect(mockUpdate).toHaveBeenCalledWith(
-      '/organizations/acme/unsubscribe/issue/9876/?_=signature-value',
-      expect.objectContaining({data: {cancel: 1}})
+      '/organizations/acme/unsubscribe/issue/9876/',
+      expect.objectContaining({
+        data: {cancel: 1},
+        query: {_: 'signature-value'},
+      })
     );
   });
 });
diff --git a/static/app/views/unsubscribe/issue.tsx b/static/app/views/unsubscribe/issue.tsx
index 7e688cf020bc..3420fbe93427 100644
--- a/static/app/views/unsubscribe/issue.tsx
+++ b/static/app/views/unsubscribe/issue.tsx
@@ -68,7 +68,12 @@ function UnsubscribeBody({orgSlug, issueId, signature}: BodyProps) {
   );
   const mutation = useMutation({
     mutationFn: (value: {cancel: number}) =>
-      fetchMutation({url: `${endpoint}?_=${signature}`, method: 'POST', data: value}),
+      fetchMutation({
+        url: endpoint,
+        method: 'POST',
+        options: {query: {_: signature}},
+        data: value,
+      }),
     onSuccess: () => {
       testableWindowLocation.assign('/auth/login/');
     },
diff --git a/static/app/views/unsubscribe/project.spec.tsx b/static/app/views/unsubscribe/project.spec.tsx
index ad2b76f0ee55..3dac779d7965 100644
--- a/static/app/views/unsubscribe/project.spec.tsx
+++ b/static/app/views/unsubscribe/project.spec.tsx
@@ -7,7 +7,7 @@ describe('UnsubscribeProject', () => {
   let mockGet: jest.Mock;
   beforeEach(() => {
     mockUpdate = MockApiClient.addMockResponse({
-      url: '/organizations/acme/unsubscribe/project/9876/?_=signature-value',
+      url: '/organizations/acme/unsubscribe/project/9876/',
       method: 'POST',
       status: 201,
     });
@@ -60,8 +60,11 @@ describe('UnsubscribeProject', () => {
     await userEvent.click(button);
 
     expect(mockUpdate).toHaveBeenCalledWith(
-      '/organizations/acme/unsubscribe/project/9876/?_=signature-value',
-      expect.objectContaining({data: {cancel: 1}})
+      '/organizations/acme/unsubscribe/project/9876/',
+      expect.objectContaining({
+        data: {cancel: 1},
+        query: {_: 'signature-value'},
+      })
     );
   });
 });
diff --git a/static/app/views/unsubscribe/project.tsx b/static/app/views/unsubscribe/project.tsx
index 6609ec5f2f1e..bcd758766e13 100644
--- a/static/app/views/unsubscribe/project.tsx
+++ b/static/app/views/unsubscribe/project.tsx
@@ -68,7 +68,12 @@ function UnsubscribeBody({orgSlug, issueId, signature}: BodyProps) {
   );
   const mutation = useMutation({
     mutationFn: (value: {cancel: number}) =>
-      fetchMutation({url: `${endpoint}?_=${signature}`, method: 'POST', data: value}),
+      fetchMutation({
+        url: endpoint,
+        method: 'POST',
+        options: {query: {_: signature}},
+        data: value,
+      }),
     onSuccess: () => {
       testableWindowLocation.assign('/auth/login/');
     },
diff --git a/static/gsAdmin/components/deleteBillingMetricHistory.spec.tsx b/static/gsAdmin/components/deleteBillingMetricHistory.spec.tsx
index 3331a4b72f52..95608bcbacaa 100644
--- a/static/gsAdmin/components/deleteBillingMetricHistory.spec.tsx
+++ b/static/gsAdmin/components/deleteBillingMetricHistory.spec.tsx
@@ -141,7 +141,7 @@ describe('DeleteBillingMetricHistory', () => {
 
       // Mock the API endpoint for deleting billing metric history
       const deleteBillingMetricHistoryMock = MockApiClient.addMockResponse({
-        url: `/api/0/customers/${organization.slug}/delete-billing-metric-history/`,
+        url: `/customers/${organization.slug}/delete-billing-metric-history/`,
         method: 'POST',
         body: {},
       });
@@ -170,7 +170,7 @@ describe('DeleteBillingMetricHistory', () => {
 
       // Check that the API call was made with the correct parameters
       expect(deleteBillingMetricHistoryMock).toHaveBeenCalledWith(
-        `/api/0/customers/${organization.slug}/delete-billing-metric-history/`,
+        `/customers/${organization.slug}/delete-billing-metric-history/`,
         expect.objectContaining({
           method: 'POST',
           data: {
@@ -219,7 +219,7 @@ describe('DeleteBillingMetricHistory', () => {
 
     // Mock the API endpoint to return an error
     const deleteBillingMetricHistoryMock = MockApiClient.addMockResponse({
-      url: `/api/0/customers/${organization.slug}/delete-billing-metric-history/`,
+      url: `/customers/${organization.slug}/delete-billing-metric-history/`,
       method: 'POST',
       statusCode: 400,
       body: {
diff --git a/static/gsAdmin/components/deleteBillingMetricHistory.tsx b/static/gsAdmin/components/deleteBillingMetricHistory.tsx
index 4023f01aee31..104584d7cbae 100644
--- a/static/gsAdmin/components/deleteBillingMetricHistory.tsx
+++ b/static/gsAdmin/components/deleteBillingMetricHistory.tsx
@@ -13,6 +13,7 @@ import {openModal} from 'sentry/actionCreators/modal';
 import {LoadingIndicator} from 'sentry/components/loadingIndicator';
 import type {Organization} from 'sentry/types/organization';
 import {apiOptions} from 'sentry/utils/api/apiOptions';
+import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {fetchMutation} from 'sentry/utils/queryClient';
 import {RequestError} from 'sentry/utils/requestError/requestError';
 
@@ -70,7 +71,12 @@ function DeleteBillingMetricHistoryModal({
   const mutation = useMutation({
     mutationFn: (dataCategory: number) =>
       fetchMutation({
-        url: `/api/0/customers/${orgSlug}/delete-billing-metric-history/`,
+        url: getApiUrl(
+          `/customers/$organizationIdOrSlug/delete-billing-metric-history/`,
+          {
+            path: {organizationIdOrSlug: orgSlug},
+          }
+        ),
         method: 'POST',
         data: {data_category: dataCategory},
       }),
diff --git a/static/gsAdmin/views/customerDetails.tsx b/static/gsAdmin/views/customerDetails.tsx
index 6466bceabba2..2f91879a4570 100644
--- a/static/gsAdmin/views/customerDetails.tsx
+++ b/static/gsAdmin/views/customerDetails.tsx
@@ -196,7 +196,12 @@ export function CustomerDetails() {
   const onToggleBillingPlatformMigrationMutation = useMutation({
     mutationFn: (params: Record<string, any>) =>
       fetchMutation({
-        url: `/_admin/customers/${orgId}/billing-platform-migration/`,
+        url: getApiUrl(
+          '/_admin/customers/$organizationIdOrSlug/billing-platform-migration/',
+          {
+            path: {organizationIdOrSlug: orgId},
+          }
+        ),
         method: 'POST',
         data: params,
       }),
diff --git a/static/gsApp/components/creditCardEdit/intentForms/setupIntentForm.tsx b/static/gsApp/components/creditCardEdit/intentForms/setupIntentForm.tsx
index f0b2d0290221..930479d453ca 100644
--- a/static/gsApp/components/creditCardEdit/intentForms/setupIntentForm.tsx
+++ b/static/gsApp/components/creditCardEdit/intentForms/setupIntentForm.tsx
@@ -10,7 +10,6 @@ import {useMutation} from '@tanstack/react-query';
 import {addSuccessMessage} from 'sentry/actionCreators/indicator';
 import {LoadingIndicator} from 'sentry/components/loadingIndicator';
 import {t} from 'sentry/locale';
-import {parseQueryKey} from 'sentry/utils/api/apiQueryKey';
 import {getApiUrl} from 'sentry/utils/api/getApiUrl';
 import {fetchMutation} from 'sentry/utils/queryClient';
 
@@ -29,9 +28,8 @@ export function SetupIntentForm(props: IntentFormProps) {
   const [errorMessage, setErrorMessage] = useState<string | undefined>(undefined);
   const [isSubmitting, setIsSubmitting] = useState(false);
 
-  const {url} = parseQueryKey(props.intentDataQueryKey);
   const {intentData, isLoading, isError, error} = useSetupIntentData({
-    endpoint: url,
+    queryKey: props.intentDataQueryKey,
   });
 
   const {mutateAsync: updateSubscription} = useMutation({
diff --git a/static/gsApp/hooks/useIntentData.tsx b/static/gsApp/hooks/useIntentData.tsx
index e2ff98f4474d..fe34ca15e32d 100644
--- a/static/gsApp/hooks/useIntentData.tsx
+++ b/static/gsApp/hooks/useIntentData.tsx
@@ -1,7 +1,7 @@
 import {useEffect, useState} from 'react';
 import {useMutation} from '@tanstack/react-query';
 
-import type {ApiQueryKey} from 'sentry/utils/api/apiQueryKey';
+import {parseQueryKey, type ApiQueryKey} from 'sentry/utils/api/apiQueryKey';
 import {fetchMutation, useApiQuery} from 'sentry/utils/queryClient';
 import type {RequestError} from 'sentry/utils/requestError/requestError';
 
@@ -17,17 +17,18 @@ interface HookResult {
 /**
  * Get payment method setup intent data.
  */
-export function useSetupIntentData({endpoint}: {endpoint: string}): HookResult {
+export function useSetupIntentData({queryKey}: {queryKey: ApiQueryKey}): HookResult {
   const [setupIntentData, setSetupIntentData] = useState<
     PaymentSetupCreateResponse | undefined
   >(undefined);
+  const {url} = parseQueryKey(queryKey);
   const [isLoading, setIsLoading] = useState(false);
   const [error, setError] = useState<string | undefined>(undefined);
   const {mutate: loadSetupIntentData} = useMutation<
     PaymentSetupCreateResponse,
     RequestError
   >({
-    mutationFn: () => fetchMutation({url: endpoint, method: 'POST'}),
+    mutationFn: () => fetchMutation({url, method: 'POST'}),
     onSuccess: data => {
       setSetupIntentData(data);
       setIsLoading(false);